round_time: A generic function for rounding date and time values
Description
A generic function for rounding date and time values
Usage
round_time(x, n, tz)
Value
If POSIXct then POSIX. If date then Date.
Arguments
x
A vector of class POSIX or Date.
n
Unit to round to. Defaults to mins. Numeric values treated
as seconds. Otherwise this should be one of "mins", "hours", "days",
"weeks", "months", "years" (plural optional).
tz
Time zone to be used, defaults to "UTC" (Twitter default)